Background. Lyme borreliosis disease results from infection by members of the Borrelia burgdorferi sensu lato complex. The most common clinical presentation of Lyme borreliosis is erythema migrans (EM). To gain knowledge of the epidemiological parameters and the risk factors of EM in Slovenia, a survey has been carried out in 2010. Methods. A short anonymous and self-administrated questionnaire was sent to 4917 notified EM patients in 2010, aiming to collect epidemiological data and assess socio-economic determinants in patients with EM. Results. Three thousand and five (61%) patients with EM returned completed questionnaires. One thousand and nine hundred twenty-nine (74%) patients noted the tick where the EM developed. The tick bite was most often located on the legs in adults and in the head/neck area in children. The time that elapsed before the tick has been removed increased significantly with age. The attached tick was most frequently overlooked in preschool children. Nearly 70% of patients believed that they contracted the infection with borrelia near home. Infection away from their permanent residence was more often the case in those with a higher level of education and in 15-49 age groups. Compared to the Slovenian general population over 14 years of age, those with a higher level of education, the unemployed and farmers were overrepresented among the EM patients. Conclusions. The risk of Lyme borreliosis is widespread in Slovenia, with some areas more affected then others. Determinants of exposure to infected ticks are different, and depend on the socio-economic status and demographic characteristics. Izhodišče. Lymska borelioza je posledica okužbe z bakterijami kompleksa Borrelia burgdorferi sensu lato. Erythema migrans (EM) je najpogostejša klinična oblika lymske borelioze. Namen raziskave je bil pridobiti epidemiološke podatke in preučiti socialno-ekonomske značilnosti prijavljenih bolnikov z EM v Sloveniji. Metode. Kratek anonimni vprašalnik je bil poslan vsem 4917 bolnikom, prijavljenih z diagnozo EM v letu 2010, da bi se zbrali epidemiološki podatki in ocenile socialno-ekonomske determinante. Rezultati. 3005 (61%) bolnikov z EM je vrnilo popolno ali delno izpolnjene vprašalnike. 1929 bolnikov (74%) je navedlo, da se je EM pojavil na mestu predhodnega vboda klopa. Vbod klopa je bil največkrat na nogah pri odraslih in v predelu glave ali vratu pri otrocih. Čas od vboda klopa do njegove odstranitve je bil značilno daljši pri starejših, pogosteje pa so ga spregledali pri predšolskih otrocih kot pri odraslih bolnikih. Približno 70% bolnikov z EM je menilo, da so se z borelijo okužili v bližini doma. Okužba zunaj kraja stalnega prebivališča je bila pogostejša pri tistih z višjo stopnjo izobrazbe in v starostni skupini 15-49 let. V primerjavi s strukturo slovenskega prebivalstva nad 14 let je bilo med bolniki z EM več tistih z višjo stopnjo izobrazbe, brezposelnih in kmetov. Zaključek. Lymska borelioza je v Sloveniji zelo razširjena, pri čemer je primerov več v nekaterih predelih. Determinante izpostavljenosti okuženim klopom so različne in odvisne od socialnoekonomskega statusa in demografskih značilnosti.